I got it to work but not using the actual id of the Html.BeginForm, I used this and this works:

$(function () {
            $("form").submit(function (e) {
                alert("onSubmit");
                onSubmit();
            });
        });

But this event fires even when the form does not validate. I either need to find a way for this event not to fire if the form does not validate or be able to check inside the event if the form validated. How do I do this?